Trigger Points

The Soleus trigger point that can cause pain in the Achilles tendon[1]. Note that the calf has two main muscles, the Gastrocnemius and the Soleus. The Soleus is under the Gastrocnemius which has been removed from this diagram.

It is common for muscles to develop 'trigger points', also called 'muscle knots'. These trigger points can be felt as small, hard lumps in the muscle that can be painful when pressed[1]. Trigger points may give rise to characteristic patterns of referred pain, including tendon pain, and often result in a restricted Range Of Motion[1].

1 Treating Trigger Points

Trigger points can be treated in a variety of ways:

Massage. A number of studies have shown that Massage is an effective treatment for trigger points[2][3][4]. Massage seems to be the most common and the easiest to perform at home.

Laser. The use of a low power laser on trigger points has been shown to produce pain reduction for 3 months[5][6]. Another study showed improvements from laser treatment, but the effect had disappeared by 6 months[7].

TENS. Transcutaneous Electrical Nerve Stimulation, or TENS, uses a mild electric current to reduce pain. TENS has been shown to reduce the pain associated with trigger points, but it does not improve the Range Of Motion, suggesting it reduces the pain but not the underlying problem[8].

EMS.Electrical Muscle Stimulation does not reduce the pain as much as TENS, but it does improve the Range Of Motion, suggesting it is improving the underlying muscle functioning[8].

Needles. The use of directly inserting a needle into a trigger point appears to be effective, but there was no difference found between dry needling (no injection) and the injecting of drugs or saline and there is a concern that the needling may be no more effective than a placebo[9].

Ultrasound. A study comparing Ultrasound plus Massage and exercise, just Massage and exercise, or a control group indicated that the Ultrasound did not improve the gains from Massage and exercise[10].

Magnets. The preliminary research suggests that magnet therapy may be effective, but more studies are required[11].

My personal experience is that trigger points can cause the muscle to be under continuous contraction, putting stress on the associated tendon. It is counterintuitive to work on a muscle that does not hurt to fix a tendon that is causing pain, but this approach has worked for me and others I know, but I have found no research to support or refute this belief.

2 Locating Trigger Points

The original manuals on trigger point theory are expensive ($100 each), but the web site triggerpoints.net is a useful online guide. I also like the iPhone/iPad app shown below, which is reasonably cheap and convenient.

Screen shot of the iPad version of the trigger point application. All the information is available freely online, but this is a nice presentation for $3.